
def main():
    X = int(input())
    if X >= 30:
        print("Yes")
    else:
        print("No")

if __name__ == "__main__":
    main() def main():
    X = int(input())
    if X >= 30:
        print("Yes")
    else:
        print("No") main X = int(input()) X int(input()) int input() input if X >= 30:
        print("Yes")
    else:
        print("No") X >= 30 X 30 print("Yes") print "Yes" print("No") print "No" if __name__ == "__main__":
    main() __name__ == "__main__" __name__ "__main__" main() main def main():
    X = int(input())
    if X >= 30:
        print("Yes")
    else:
        print("No") def main():
    X = int(input())
    if X >= 30:
        print("Yes")
    else:
        print("No") main

def main():
    X = int(input())
    if X >= 30:
        print("Yes")
    else:
        print("No")

if __name__ == "__main__":
    main()